Patent Document 1 discloses a virtual network constructing device that realizes end-to-end security for each service, security between services at a client, and scalability for a large-scale system. According to this document, when a client selects an available service in launcher software transmitted from a path control server after the client's authentication request has been accepted, a corresponding path constructing request is transmitted to the path control server. The path control server issues the client an instruction for connecting to a base router, and also issues the base router an instruction for connecting to the client. The document recites that an in-base VLAN can be dynamically constructed between the client and the base router as a result.
Patent Document 2 discloses a system for managing customers in a hierarchical manner. Further, Patent Document 3 discloses a peer-to-peer network capable of providing a new network topology.
Non-Patent Document 1 proposes a technology called OpenFlow. OpenFlow treats communication as an end-to-end flow, and performs path control, failure recovery, load balancing, and optimization for each flow. An OpenFlow switch that functions as a forwarding node operates according to a flow table appended or updated by an OpenFlow controller according to OpenFlow protocol. In the flow table, pairs of a packet matching rule that specify a packet and an action such as outputting the packet to a specific port, discarding it or rewriting a header are registered as flow entries. When there is a corresponding entry, the OpenFlow switch processes a received packet according to an action written in the entry, and notifies the OpenFlow protocol of the reception of the packet when there is no corresponding entry.    [Patent Document 1] Japanese Patent Kokai Publication No. JP-P2009-135805A    [Patent Document 2] Japanese Patent Kohyo Publication No. JP-P2007-525728A    [Patent Document 3] Japanese Patent Kokai Publication No. JP-P2008-306725A    [Non-Patent Document 1] McKeown, Nick et al., “OpenFlow: Enabling Innovation in Campus Networks,” [online], [searched on Jul. 17, 2009]